In the biggest donation of its kind, General Motors, the world’s largest automaker, is giving $10 million to protect 30,000 acres of coastal rainforest in southern Brazil, the Nature Conservancy said last week. GM may get pollution credits sometime in the future for preserving the forest and its ability to absorb carbon dioxide from the air. The land will be owned and managed by a Brazilian group. In other you-gotta-love-those-guys corporate news, Shell on Thursday renewed its pledge not to drill for oil and gas in Bangladeshi forests that are home to endangered Royal Bengal tigers. Environmentalists protesting at the company’s annual shareholder meeting wanted the company to promise also to stay out of a bigger wetland area surrounding the forests.